<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>

<script language="javascript">
function myJsFunction(){
alert("nihao");
}
</script>
input name="button" value=" " type=" " onclick="myJsFunction"


<img src="" id="">
<script language="javascript" type="text/javascript">
var lag=document.getElementById("scau_img_download");
img.onclick=function(){
	alert("scau welcome");
}
</script>

</body>
</html>